Lots of things would be nice ... but they aren't practical (or affordable).
Zoom is one of these.
You can get a zoom lens with the Z3 camera or more expensive and heavier X5.
But you still have to deal with problems of weight and vibration so your zoom range will be modest.
You won't get a spy telescope lens on a consumer drone with current technology.

Even if it was possible, there should be no legal problems.
Long lenses are completely legal on the ground or in manned aircraft - why should there be a special case for cameras on drones?

You can't have whatever level of zoom you like in post production.
What you can do is quite limited.
You can only go in so far and beyond that you are looking at pixelated mush.
Digital zoom isn't useful at all.

The Phantom 4, when used with a recent iOS device will give you a 2X zoom. Just like with a smart phone or tablet, you spread your fingers to zoom and pinch them to return to the normal screen. I do not know if it is a digital zoom or not, but it probably is digital.

It has not reached the Android community yet, bummer. Maybe I should check again!

You can send a microphone and recorder up separately for sound. I bought a GoPro mount and sent one up. The video is useless (vibration), but it does record the sound which can be lined up with the video from the camera on the gimbal.